The present disclosure relates generally to well drilling operations and, more particularly, to a method and system for controlling fluid contact with a borehole wall during wellbore operations.
During the course of a typical well drilling operation, the drill bit creates a hole with a somewhat larger diameter than the diameter of the corresponding drill string, creating an annular space between the drill string and borehole wall. During most drilling operations, this annular space must be filled to maintain integrity of the drilling operation. For example, a fluid placed in the annular space may be used to compensate for the pressure differential between the drill string interior and the annular space. In addition, the fluid placed in the annular fluid may be used to maintain formation pressure, which lowers the stress on the rock and thereby maintains the integrity of the formation.
Well drilling operations may require drilling through a variety of geological formations of differing properties. These formations can also be sensitive to particular conditions. Where the properties of one fluid might contribute to the integrity of one type of formation, that same fluid might be destructive to a second formation. These competing geological formations may present a challenge to a well drilling operation when both must be drilled through to reach the goal. The importance of managing the chemistry of fluid exposed to geological formations increases as the depth of the desired well increases, thereby increasing the length of exposure to adverse fluids and increasing the risk of formation collapse.
While embodiments of this disclosure have been depicted and described and are defined by reference to exemplary embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.